ABSTRACTSA new X‐ray fluorescent analyser is described which uses a miniature X‐ray tube or radioisotope source as alternative means of primary excitation. The advantages of this approach as compared to previous methods, particularly where elements low in the periodic table are concerned, is discussed.The second part of the paper describes an application of the technique. The non‐destructive analysis of valuable ceramics, where elements low in the periodic table are important for differentiation purposes, has previously presented a problem. By using the ‘Isoprobe’such measurements are possible. In this instance the separation of early Chinese porcelains into Northern and Southern production groups is shown to be possible. Although samples have been ground from the wares for comparison with optical emission spectrometry, it is shown that analysis of the unglazed portions of the pots themselves gave simila